Cyber Resilience

CVE-2026-27854

Memory Safety in Powerdns Dnsdist 1.9.0 – 1.9.12

Memory Safety
Published
31 March 2026
Modified
25 July 2026
Patch / advisory
View advisory
CVSS Score v3.1 4.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L
EPSS Score 0.0047 39th percentile
Risk Priority 40 floored blend · peak EPSS

Summary

CVE-2026-27854 is a medium-severity Use After Free (CWE-416) vulnerability in Powerdns Dnsdist. Its CVSS base score is 4.8 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked at the 39th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-27854 is a use-after-free vulnerability (CWE-416) affecting DNSdist, a DNS load balancer. The issue arises when custom Lua code invokes the DNSQuestion:getEDNSOptions method on a DNS packet that has been modified after initial processing. An attacker can trigger this by sending crafted DNS queries, leading to a reference to freed memory.

A remote, unauthenticated attacker can exploit this vulnerability over the network with no user interaction required, though it demands high attack complexity (CVSS:3.1 score of 4.8; AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L). Exploitation may result in a process crash, causing a denial of service, with potential low-impact confidentiality exposure due to the memory corruption.

Mitigation details are available in the PowerDNS security advisory for dnsdist at https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-02.html.

EU & UK References

Vulnerability Data

An attacker might be able to trigger a use-after-free by sending crafted DNS queries to a DNSdist using the DNSQuestion:getEDNSOptions method in custom Lua code. In some cases DNSQuestion:getEDNSOptions might refer to a version of the DNS packet that has…

more

been modified, thus triggering a use-after-free and potentially a crash resulting in denial of service.

CWE(s)
CWE-416

Related Threats

MITRE ATT&CK Enterprise Techniques

T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-33259Same vendor: Powerdns
CVE-2025-26681Shared CWE-416
CVE-2025-48543Shared CWE-416
CVE-2026-54127Shared CWE-416
CVE-2026-50323Shared CWE-416
CVE-2024-38078Shared CWE-416
CVE-2025-21929Shared CWE-416
CVE-2026-53025Shared CWE-416
CVE-2024-47748Shared CWE-416
CVE-2026-60002Shared CWE-416

Affected Assets

powerdns
dnsdist
1.9.0 — 1.9.12 · 2.0.0 — 2.0.3

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 3 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V1.4.3

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can discover use-after-free bugs through dynamic analysis or fuzzing.

SA-8 Security and Privacy Engineering Principles partial match

Engineering principles can require memory-safe constructs or languages that structurally avoid introducing use-after-free.

SC-39 Process Isolation partial match

Process isolation confines the blast radius of use-after-free memory corruption to a single execution domain.

SI-16 Memory Protection partial match

Memory protection controls limit exploitation impact by blocking unauthorized code execution from dangling pointers.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly incorporate memory-safety tooling and reviews that prevent most use-after-free defects.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover use-after-free issues via scanning or analysis but do not prevent their introduction.

PR.PS-02 partial match
prevents

Routine patching removes known use-after-free instances after they have been introduced in released software.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development can detect use-after-free bugs before release.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC mandates memory-safety practices that reduce use-after-free defects.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify memory-management rules that mitigate use-after-free.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles include memory-safety design choices that limit use-after-free exposure.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly prescribe avoidance of use-after-free patterns.

A.8.32 Change management partial match
prevents

Change-management processes help ensure memory-safety fixes are deployed consistently.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (1 rule)
  • V-248592 OL 8 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416
RHEL 8 (1 rule)
  • V-230279 RHEL 8 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416
RHEL 9 (1 rule)
  • V-257794 RHEL 9 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416

References